Interplanetary rendevous orbits and Oberth effect

[VoidFoo]

When choosing what orbit to start out with when doing a rendevous coming from interplanetary transfer, is it better to do a lower orbit or higher orbit than the target?

For example, I have a refueling station in circular orbit around Duna. I send a ship to Duna, and when arriving I burn retrograde to go into a circular orbit around Duna, but at a different altitude than the station. Then I can do an easy rendevous by dragging around a maneuver node until I get a close separation.

So is there a rule of thumb as to what starting orbit is more efficient, delta-v wise, when coming in from an interplanetary transfer orbit?
- If I go for a low orbit, I get good Oberth Effect, but it feels weird because I cross the target orbit to get into the lower orbit, then during rendevous go back up.
- If I go for a high orbit, it feels like I haven't "wasted" anything because I don't cross the target orbit.

[Superfluous J]

For me, I want my incoming orbit's Pe to touch the station's orbit. I burn at that Pe to get an orbit around the planet/moon, then at Ap do the cheaper burn to align my orbit, then another burn back at Pe to get an encounter, and finally on the next orbit meet the station.

Once you have that basic set of steps down you can optimize, like setting up the meeting of the station on the same burn that you get your orbit. Or algning your orbit on entry to be as close to aligned with the station as possible.

[AHHans]

[*bleep* Apparently I closed the tab with my first answer without sending the answer. Maybe spending too much time in real-life planes and trains is affecting my brain...]

On 12/23/2019 at 11:24 PM, VoidFoo said:

When choosing what orbit to start out with when doing a rendevous coming from interplanetary transfer, is it better to do a lower orbit or higher orbit than the target?

If you think about it, then this is the same problem as boosting into an interplanetary transfer straight from a "gateway orbit" or first lowering your PE and then boosting from there. (Just invert the time-axis, you are allowed to do that in Newtonian physics.) Someone(*) already looked into that, and the result is that it depends on how much speed (or energy) you'll need to shed: if you come from (or go to) far away (like from Jool to Kerbin or vice versa) then burning at a low PE is better, if it is just between Duna and Kerbin, then you'll loose more to adjusting your orbit after capture than you'll gain from burning at low PE.

(*) The spreadsheet in here: https://forum.kerbalspaceprogram.com/index.php?/topic/175831-standard-orbits-for-interplanetary-shuttles-fuel-stations/&do=findComment&comment=3400067

Edited December 31, 2019 by AHHans
fixed typo